Field of the Invention
The present invention relates to a wireless power transfer system for a plurality of apparatuses, a control method of the wireless power transfer system, a wireless power transmitting apparatus, a control method of the wireless power transmitting apparatus, and a storage medium.
Description of the Related Art
In recent years, apparatuses such as cellular phones which use rechargeable batteries are popularly used. A system for charging a rechargeable battery is configured by a primary-side apparatus which transmits power to the rechargeable battery, and a secondary-side apparatus which receives power.
In such a charging system, a technique for displaying a charging state of a rechargeable battery on the primary side is available (Japanese Patent Laid-Open No. 8-019189). Also, a technique for displaying a charging state of a rechargeable battery on a secondary-side apparatus is available (Japanese Patent Laid-Open No. 7-241045).
Furthermore, a technique for transferring power to a plurality of apparatuses using electromagnetic induction or electromagnetic resonance is available (Japanese Patent Laid-Open No. 2008-017592, U.S. Patent Application Publication No. 2009/0140690). Moreover, a wireless power transfer technique, which communicates so as to supply power to a secondary-side apparatus that uses a different voltage or current, is available (Japanese Patent Laid-Open No. 6-133476).
However, in a wireless charging system which can wirelessly charge a plurality of secondary-side apparatuses, the power transmitting capability of a primary-side apparatus has an upper limit specified by that wireless charging system.
On the other hand, in the wireless charging system, a restriction about the position of the secondary-side apparatus during charge is relatively moderate because the primary-side apparatus and secondary-side apparatus need not be connected. For this reason, there is a case that a predetermined number or more of secondary-side apparatuses are located within a wirelessly chargeable region and not charged wirelessly over the power transmitting capability of the primary-side apparatus.
In this case, the following phenomena may occur. That is, the charging times of the respective secondary-side apparatuses may be prolonged, and a specific secondary-side apparatus may not be charged. However, with the conventional technique, the user does not receive any information indicating that such phenomena have occurred.
The present invention provides a technique which allows the user to recognize information regarding charging speed generated at the time of wireless power transfer.